The excavating of ore or other minerals is performed typically at mines by drilling and by loading a number of pluralities of deep holes in an advantageous grouping in terms of the blasting technique. Compressed air, or a compressed air-water mix, blown via the boring pipe is used in drilling the deep holes to transport the rock material that is detached by the drill bit out of the hole. Due to the action of the compressed air, rock material typically flies into a small heap around the borehole. The ore being sought is not evenly distributed in the bedrock of the mining area, but instead adjoining rock formations having a smaller or non-existent ore content are mixed up with the ore deposit. The excavation of encasing rock cannot be avoided, but it is worth minimizing the progression of the encasing rock into the crushing phases and ore cleaning phases. From the viewpoint of the ore cleaning process, it is advantageous to know in advance as accurately as possible the grade of the crushed ore material entering the process. The grade of the ore material in the ore intended to be excavated is first ascertained with trial boring and in the production drilling stage by collecting rock samples, into sample bags with a shovel, from the piles of rock material produced around the boreholes in the drilling. The sample collecting work is performed manually and requires an employee to move about the drilling field. Drilling field conditions are typically dusty and the nature of the flying dust detaching from the piles can be detrimental to the health of the employee collecting the samples. From the collected samples a sample is made by splitting a number of times, from which sample the content of the target minerals is determined. A weakness with pile samples is that it is no longer possible to ascertain from the rock material taken from a pile information about the depth of adjoining rock deposits or ore deposits from the drilling level. A sample taken from a pile represents a sort of hole average. It is also known in the art that some of the target mineral has possibly escaped along with the finer material carried by the wind, so remaining in the pile is a higher proportion of adjoining rock in relation to the target mineral. Known solutions to the problem are to install on the boring pipe a collar, or suchlike system, covering the whole borehole to collect rock material coming out of the hole and to split the whole amount of material a number of times, automatically or manually, or to install on the collar a flow guide and turn part of the flow into a separate bag functioning as a sample collector.
Publication U.S. Pat. No. 4,650,013 presents a subsurface sampling apparatus, by means of which subsurface samples can be taken from a hole drilled in the ground. It has a bag-like collection container, in which the subsurface samples are collected. The subsurface samples are fed into the collection container via a mouth piece that is in an inclined attitude on the edge of a vertical pipe. The area of the borehole is covered with an elastic cover.
Particular drawbacks in sampling apparatuses according to prior art are poor sampling accuracy and the complex structure of the apparatus.